Electric induction-furnace.



J. FUNCK.

ELECTRIC INDUCTION FURNACE. APPLICATION FILED FEB. 2, 1916.

Patented May 22,1917.

v UNITED STATES PATENT OFFICE.

JAKOB FUNCK, OF CHARLOTTENBURG. GERMANY, ASSIGNOR TO THE GRONDAL KJELLIN COMPANY, LIMITED, OF LONDON,

ENGLAND.

ELECTRIC INDUCTION -FURNACE.

Specification of Letters Patent.

' Patented May 22, 1917.

Application filed February 2, 1916. Serial No, 75,880.

, crease the durability of the linings ofthe hearths thereof by making the same much denser' and harder than furnace linings formed in the usual manner.- It has been customary to form the lining of the hearth of an electric induction furnace by ramming the magnesite or similar material in a plastic condition around a templet arranged in the furnace hearth and after removing the templet, consolidating or baking the mass by means of heating, rings suitably arranged in the said hearth. This method of forming the lining is unsatisfactory as the lining expands owing to its exposure to the air during the heating or sintering operation so that the densitv and hardness of the lining is detrimentally affected.

According to thisv invention the lining material is placed around a templet or former in the hearth of the furnace and the templet or former is then utilized for heating and consolidating the material and forming the lining in, situ. In this manner air is totally excluded from the lining during the heating operation and moreover the templet or former eflectively'prevents the lining material expanding during the sintering and setting thereof. Again, the exclusion of air from thelining material enablesthe bindin agent used therewith to be thoroughly co ed and not burned on the surface of the lining as would be the case if the material were exposed to the air during the heating operation.

In order that the inventionmay be clearly understood and readily carried into effect the same will now be more fully described by the aid of the accompanying drawing, in which Figure-1 is a'plan of a furnace showing the templet and lining in position.

Fig. 2Jis a section on line AA of Fig. 1 showing the lining rammed to the templet.

Fig. 3 is a fragmentary section showing a. modification.

, when it is melted the resultant volume of Fig. +l a sectional view of the templet.

The templet or former a employed is made of metal and conforms with the shape of-the furnace hearth. \Vhen thelining material Z) is in position the templet a closely fits and entirely covers the inner surface thereof so as to effectively exclude air and preventexpansion during the heating operation. The dimensions of the. templet a; are such that molten metal will be equal to the volume of the metal bath of the furnace, so that the molten metal will serve as the first charge for the furnace.

It is immaterial how the templet or former a. is constructed. that is, whether it consists of only one hollow piece provided with ribs 0 and occupying the whole hearth or whether it consists of several pieces provided with suitable reinforcements. It is important however that the templet-should extend to the upper edge of the lining and rest closely agamst the same. It may not always be .desirable to have the metallic body of the templet or former in contact with the lining of the furnace and in this case a layer of asbestos or similar material (Z may be interposed between the adjacent surfaces of the templet and lining see Fig. 3. The metallic body and enveloping shield of asbestos or other material would then constitute the templetor former and in a similar manner to the arrangement previously described would effectively exclude air and prevent the expansion of the lining during the heating operation.

What I claim and desire to secure by Letters Patent of the United States is 1. A method of lining the hearths of electIic induction furnaces, consisting in placing the lining material around a templet in the furnace hearth, utilizing the templet for heating and consolidating the material to form the lining in situ and finally fusing the templet;

2. 'A method of lining the hearths of electric induction furnaces, consisting in placing the lining material around a templet in the furnace hearth so that the templet closely fits and entirely covers the inner surface of the lining material utilizing the templet for heating and consolidating the material to form the lining in sz'tu and finally fusing the templet to form the first charge for the furnace.

3. A method of lining the hcarths of electric induction furnaces, consisting in placing the lining material around a templet comprising a single hollow metallic element arranged in the furnace hearth so that the templet closely fits and entirely covers the inner surface of the'lining material, utilizing the templet for heatingv and consolidating the material to form the lining in situ and finally fusing the templet so that the metal thereof, when in the molten state, constitutes the initial metal bath for the furnace.

4. A method of lining the hearth's of electric induction furnaces, consisting in placing the lining material around a templet comprising several hollow metallic elements With suitable reinforcementsarranged 1n the furnace hearth so that the templet closely fits and entirely covers the inner surface of the lining material, utilizing the templet for heating and consolidating the material to form the hning in situ and finally fusing the templet so that the metal thereof. when in the molten state. constitutes the initial metal bath of the furnace.

5. A method of lining the hearths of electric induction furnaces, consisting in placing the lining material around a metal templet which is provided with an enveloping sheath of asbestos or similar material so that the templet closely fits and entirely covers the inner surface of the lining material, utilizing the templet for heating and consolidating th material to form the lining in situ and finally fusing the templet.

J AKOB FUNCK. 

